(1) Field of the Invention
The present invention relates to a dispenser device, especially to an easily-controlled dispenser device with adjustable injecting direction, accurate, precise and uniform volume per-injection.
(2) Prior Art Description
Since the first report on fat grating appeared in medical literature by Dr. Neüber in 1893, autologous fat graft serving as a soft tissue filler was performed by many surgeons to fill (or level) depressed scars, minimize facial wrinkles, rejuvenate facial contours, and even reinforce external shape of lips or nasion for over one century[1]. The fat grafting was regarded for years as an excellent procedure for reconstructing soft tissue defects or as an autologous filler, and thus has been applied in fields of reconstructive, aesthetic and plastic surgery.
A successful fat grafting surgery depends on four major steps during the procedure: harvesting of fat, processing of fat, refinement of fat and transplantation of the purified fat, which is the final and cardinal step of all[2,3]. Surgeons and scientists in this field have proposed various fat grating techniques; however, no convincing resolutions have been concluded yet[4-19]. The transplantation of fat requires the delicate hand-operation of an experienced surgeon. Therefore, the key to the high fat survival rate with low morbidity is critically dependent on surgeon's skill to inject minute volume of the fat if needed. An appropriate instrument is thus desirable for a surgeon to perform a successful procedure as such. On the other hand, morbidities of fat grafting such as absorption, infection, embolism, cyst formation, calcification, ossification, necrosis, asymmetry, skin necrosis/fistula formation, iatrogenic neurovascular injuries are closely correlated with improper, uneven, or most oftentimes, excessive transplantation of fat during the fat grafting procedure[20].
Dr. Coleman, the renowned American plastic surgeon, proposed the concept of “Structure Fat Graft” which emphasized that the fat parcel should be layer by layer arranged with the injection volume less than 1/10 cc per parcel (even 1/30˜ 1/50 cc is requested in special site such as peri-orbital areas)[21]. By avoiding the central necrosis of fat graft induced by over-injection in each parcel, the complications and morbidities of fat grafting will be minimized.
Dr. Carpaneda in Brazil pointed out about 40% survival tissue was observed within the peripheral zone (1.5±0.5 mm to peripheral margin) in his eminent article[4]. He addressed later that thickness and geometrical shape are the key factors to a successful fat transplantation and concluded that the radius of fat graft either in spherical shape or cylindroid shape should be less than 2 mm to get a higher fat survival rate[22]. Based on the theory postulated by Carpaneda, the volume of fat could be calculated (if each fat droplet is presumed to be a spherical shape) with the following formula:
The volume of a Globe with 1.0 mm in radius is 4.2 mm3 
The volume of a Globe with 1.5 mm in radius is 14.1 mm3 
The volume of a Globe with 2.0 mm in radius is 33.5 mm3 
The Volume of a globe is calculated by (4/3)πr3, r: Global radius
Injection frequencyGlobal radiusGlobal volumeper 1 cc (1000 mm3) fat graft1.0 mm 4.2 mm32401.5 mm14.1 mm3702.0 mm33.5 mm330
Consequently, in fat grafting the minimal injection frequency should be at least 30 per cc to achieve the best survival rate.
Although there are devices in the market to assist the surgeon, the optimal device currently available has a per-injection volume of up to 1/10 cc (some may even yield as high as 0.5 or 1 cc per-injection!)[23-24]. An assumed successful surgery may end up in vain due to the lack of ideal tools. This situation reflects what Faith Baldwin has said “Character builds slowly, but it can be torn down within incredible swiftness.”
The DISPOS-A-JECT™ SYSTEM series from Byron Medical, delivers 0.1 cc with each pull of trigger[23], which will cause inevitable morbidities/complication of fat grafting surgery and thus is not well accepted by surgeons. Cytori Therapeutic., producer of the innovative PureGraft™ system for fat grafting, claims its CellBrush™ a cutting edge device for the surgeons to yield a promising result in fat grafting at a 0.15 cc per injection[25]. However, the critical requirement for a successful fat grafting is not met yet. That is, to deliver every fat droplet at a volume between 1/30 cc and 1/240 cc as evidenced in literature and practical medicine[4.22].
Byron Medical supplies DISPOS-A-JECT™ SYSTEM (FIG. 1) with a minimum volume of 1/10 cc per-injection, which fails to meet the basic requirement of a smaller volume, i.e. 1/30 cc to 1/50 cc, per-injection, Besides, this system uses exclusively 1 cc BD Luer-Lok syringes. The lack of the flexibility in the choice of regular Luer-Slip 1 cc syringes available in any hospital or clinic could cause inconvenience and unpopularity.
Referring to FIG. 1 for DISPOS-A-JECT™ SYSTEM operated in fat graft surgery: the SYSTEM adapter (12) in place of a plunger (11) removed from a syringe (1) in advance is jointed to the syringe (1) for propelling fat inevitably exposed in air which raises doubts about fat cells infected and a lower survival rate. Furthermore, a fixed angle between the SYSTEM gun's surface and an infiltration cannula (13) (or a pinhole (14)) is detrimental to surgery's flexible adjustment in injection angles and hence causes a deviated injection plane or failure of injection during surgery for fat injected clinically.
Recent articles have proved that concurrent injection of human adipose-derived stem/stromal cells (ADSCs) with fat graft promotes efficiently the fat survival rate[19,26]. Adding nutritious medium or platelet-rich plasma (PRP) which is rich in variable growth factors and cytokines is reported to enhance the survival of the fat[27]. However, the even mixture of fat graft with ADSCs, medium or PRP is not easily attainable. A debating issue in practice such as unevenly-distribution of the additives could give rise to a failure for optimal effect.
With the above disclosure, a new device developed for fat graft to overcome various drawbacks from prior arts is indispensable to fulfill the requirements for precise volume control, airtight equipment, convenient operation, cost effectiveness, and micro-dosage (between 1/30 and 1/240 cc per-injection) along with other considerations such as combined evenly transplantation of cells (e.g., stem cells), biomaterials, or growth factors. Note:    [1] Neüber, F. Fettgraftation. Zentrabl. Chir. 22: 66, 1893.    [2] Sommer, B. and Sattler, G. Current concepts of fat graft survival: histology of aspirated adipose tissue and review of the literature. Dermatol. Surg. 26: 1159, 2000.    [3] Katz, A. J. A novel device for the simple and efficient refinement of liposuctioned tissue. Plast. Reconstr. Surg. 107: 595, 2001.    [4] Carpaneda, C. A. Study of the histologic alterations and viability of the adipose graft in humans. Aesthet. Plast. Surg. 17: 43, 1993.    [5] Sattler, G. and Sommer, B. Liporecycling: a technique for facial rejuvenation and body contouring. Dermatol. Surg. 26: 1140, 2000.    [6] Sommer, B. and Sattler, G. Current concepts of fat graft survival: histology of aspirated adipose tissue and review of the literature. Dermatol. Surg. 26: 1159, 2000.    [7] Yaron, H. S. An integrated approach for increasing the survival of autologous fat grafts in the treatment of contour defect. Plast. Reconstr. Surg. 104: 945, 1999.    [8] Gonzalez, A. M. An alternative method for harvest and processing fat grafts: an in vitro study of cell viability and survival. Plast. Reconstr. Surg. 120: 285, 2007.    [9] MacRae, J. W. Ex vivo fat graft preservation—effects and implications of cryopreservation. Ann Plast Surg. 52: 281, 2004.    [10] Katz, A. J. A novel device for the simple and efficient refinement of liposuctioned tissue. Plast. Reconstr. Surg. 107: 595, 2001.    [11] Donofrio, L. M. Structural autologous lipoaugmentation: a pan-facial technique. Dermatol. Surg. 26: 1129, 2000.    [12] Coleman, S. R. Structural Fat Grafting. St. Louis, Mo.: Quality Medical, 2004. Pp. 30-175.    [13] Guerrerosantos, J. Aesthetic facial contour augmentation with microlipofilling. Aesthet. Surg J. 23: 239, 2003.    [14] Pu, Lee. L. Q. Long-term preservation of adipose aspirates after conventional lipoplasty. Aesthet. Surg J. 24: 536, 2004.    [15] Shiffman, M. A. and Mirrafati, S. Fat transfer techniques: the effect of harvest and transfer methods on adipocyte viability and review of the literature. Dermatol. Surg. 27: 819, 2001.    [16] Rohrich. R. J. The fat compartments of the face anatomy and clinical implications for cosmetic surgery. Plast. Reconstr. Surg. 119: 2219, 2007.    [17] Chajchir, A. and Benzaquen, I. Fat-grafting injection for soft-tissue augmentation. Plast. Reconstr. Surg. 84: 921, 1989.    [18] Testsuo, S. and Samuel M. L. Liposuction and lipotransplants for facial rejuvenation in the Asian patient. International J. Cosmet. Surg. Aesthet. Dematol. 5: 165, 2003.    [19] Yoshimura, K. Cell-assisted lipotransfer for cosmetic breast augmentation: supportive use of adipose-derived stem/stromal cells. Aesthet. Plast. Surg. 32: 48, 2008.    [20] Khawaja H. A. Fat Transfer Review: Controversies, Complications, Their Prevention, and Treatment. Int. J. Cosmet. Surg. 4: 131, 2002.    [21] Coleman, S. R. The technique of periorbital lipoinfiltration. Oper. Tech. Plast. Reconstr. Surg. 1: 120, 1994.    [22] Carpaneda, C. A., and Riberio, M. T. Percentage of graft viability versus injected volume in adipose autografts. Aesthet. Plast. Surg. 18: 17, 1994.    [23] http://www.byrondirect.com/download/downloads/Catalog/Subsecti ons/Micro-Infiltration.pdf    [24] Fulton, J. E. Breast Contouring with “Gelled” Autologous Fat: A 10-Year Update. Int. J. Cosmet. Surg. Aesth. Dermatol. 5: 155, 2003    [25] http://www.cytori.com/Store/ProductDetail.aspx?ProductId=5&Pro ductFamilyId=4&Reload=1    [26] Yoshimura, K. Progenitor-Enriched Adipose Tissue Graftation as Rescue for Breast Implant Complications. Breast J. 12: 169, 2009.    [27] Cerervelli, V. Autologous platelet-rich plasma mixed with purified fat graft in aesthetic plastic surgery. Aesthet. Plast. Surg. 33: 716, 2009.